Package, light emitting device, and methods of manufacturing the package and the light emitting device

ABSTRACT

A package for mounting a light emitting element includes a recess; a pair of lead electrodes exposed at a bottom surface of the recess; a plating layer covering a surface of each of the pair of lead electrodes; and a resin molded body retaining the pair of lead electrodes, and forming an area between the pair of lead electrodes at the bottom surface of the recess and a lateral surface of the recess. At least one of the lead electrodes has a front surface protrusion that is linearly formed along the resin molded body at the bottom surface of the recess and along a periphery of the bottom surface of the recess, and a back surface protrusion that is formed at a position at a back surface opposite to a position of the front surface protrusion, and at least a tip of each of the front surface protrusion and the back surface protrusion is exposed outside the plating layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/978,641, filed on Dec. 22, 2015, which claims priority to JapanesePatent Application No. 2014-263694, filed on Dec. 25, 2014, thedisclosures of which are hereby incorporated by reference in theirentireties.

BACKGROUND

1. Technical Field

The present disclosure relates to a package, a light emitting device,and methods of manufacturing the package and the light emitting device.

2. Description of the Related Art

A method of manufacturing a light emitting diode (hereinafter referredto as an “LED”) includes molding a package, and an LED is manufacturedthrough the molding step. In manufacturing an LED, transfer molding hasbeen typically employed, in which a lead frame is set in a mold andliquid resin is injected. However, with such a method of manufacturingan LED, the resin flows into a gap between the lead frame and the mold,which may result in generation of resin burrs. Such resin burrs maycause a bonding failure of LED elements and/or wires, so the burrs mustbe removed. Accordingly, in conventional manufacturing of an LED, themolding is always followed by removing the burrs.

In such a method of manufacturing an LED, examples of ways to preventgeneration of resin burrs include optimizing conditions in the molding,increasing the pressing force of the mold, reducing the number of LEDsmolded with a single lead frame, increasing the viscosity of resin toreduce flowability or the like.

Further, JP 2014-29995 A discloses that, in a lead frame provided with aplating layer on its surface, burrs can be reduced by allowing theplating layer to rise and protrude at the border of a portion where ametal portion is desired to be exposed (an LED mounting portion, a wirebonding portion), or by allowing part of the lead frame body to rise andproviding plating thereon to protrude.

The mold disclosed in JP 2014-29995 A is provided with a projectionhaving a shape corresponding to a recess of a package. Accordingly, themold has the following structure. When the lead frame is pressed, theprojection of the mold abuts and is pressed against the plating raisedat the border of the LED mounting portion, or a protrusion where thelead frame itself is raised and provided with plating. Thus, entry ofresin which will become burrs is prevented.

However, according to the method of manufacturing disclosed in JP2014-29995 A, in the case where the protrusion is formed by raising theplating layer, the protrusion may be crushed by the mold at the time ofpressing the mold, and the mold may also be brought into contact withthe LED mounting portion. This contact results in formation of a mark inthe LED mounting portion that reduces the glossiness of the plating,which may lead to a reduction in the output of the LED.

SUMMARY

The embodiments of the present disclosure provide a package and a lightemitting device in which the generation of burrs is suppressed, andmethods of manufacturing the package and the light emitting device whilesuppressing the generation of burrs.

A package for mounting a light emitting element according to certainembodiments of the present disclosure includes a recess, a pair of leadelectrodes exposed at a bottom surface of the recess, a plating layercovering a surface of each of the pair of lead electrodes, and a resinmolded body that holds the pair of lead electrodes and is exposedbetween the pair of lead electrodes at the bottom surface of the recessand forms a lateral surface of the recess. At least one of the pair oflead electrodes has a front surface protrusion that is a protrusionlinearly formed along the resin molded body at the bottom surface of therecess and along a periphery of the bottom surface of the recess, and aback surface protrusion that is a protrusion formed at a position at aback surface opposite to a position of the front surface protrusion. Atleast a tip of each of the front surface protrusion and the back surfaceprotrusion is exposed outside the plating layer.

Further, a package for mounting a light emitting element according tocertain embodiments of the present disclosure includes a recess, a pairof lead electrodes exposed at a bottom surface of the recess, a platinglayer covering a surface of each of the pair of lead electrodes, and aresin molded body that holds the pair of lead electrodes and is exposedbetween the pair of lead electrodes at the bottom surface of the recessand forms a lateral surface of the recess. At least one of the pair oflead electrodes has a front surface protrusion that is a protrusionlinearly formed along the resin molded body at the bottom surface of therecess and along a periphery of the bottom surface of the recess, and aback surface protrusion that is a protrusion formed at a position at aback surface opposite to a position of the front surface protrusion. Thefront surface protrusion may have a width of 110 μm or more.

Still further, a light emitting device according to certain embodimentsof the present disclosure includes the package, and a light emittingelement accommodated in the recess of the package and mounted on one ofthe pair of lead electrodes.

Still further, a method of manufacturing a package for mounting a lightemitting element according to certain embodiments of the presentdisclosure includes, providing a pair of lead electrodes, each made of ametal plate, the metal plate of at least one of the pair of leadelectrodes being processed to have a front surface protrusion and a backsurface protrusion, the front surface protrusion being formed in acircular shape to surround a region for mounting a light emittingelement, and a back surface protrusion being formed at a position at aback surface of the metal plate opposite to a position of the frontsurface protrusion; forming a plating layer on a surface of each of thepair of lead electrodes such that at least a tip of each of the frontsurface protrusion and the back surface protrusion is exposed; forming apackage that defines a recess by the pair of lead electrodes and a resinmolded body, the forming including using a mold having an upper moldpart having a projection having a shape corresponding to the recess anda lower mold part on which the first lead electrode and the second leadelectrode are to be placed; placing the first lead electrode and thesecond lead electrode in predetermined positions on the lower mold partso that the first lead electrode and the second lead electrode are setbetween the upper mold part and the lower mold part and that the exposedtip of the front surface protrusion abuts the upper mold part and theexposed tip of the back surface protrusion abuts the lower mold part;pressing the upper mold part against the pair of lead electrodes;injecting a resin into the mold that is in contact with the pair of leadelectrodes; curing the injected resin to harden the resin molded body;and removing the upper mold part from the lower mold part.

Still further, a method of manufacturing a package for mounting a lightemitting element according to certain embodiments of present disclosureincludes, providing a pair of lead electrodes, each made of a metalplate, the metal plate of at least one of the pair of lead electrodesbeing processed to have a front surface protrusion and a back surfaceprotrusion, the front surface protrusion being formed in a circularshape to surround a region for mounting a light emitting element, and aback surface protrusion being formed at a position at a back surface ofthe metal plate opposite to a position of the front surface protrusion;forming a plating layer on a surface of each of the pair of leadelectrodes; forming a package that defines a recess by the pair of leadelectrodes and a resin molded body, the forming including using a moldhaving an upper mold part having a projection having a shapecorresponding to the recess and a lower mold part on which the firstlead electrode and the second lead electrode are to be placed; placingthe first lead electrode and the second lead electrode in predeterminedpositions on the lower mold part so that the first lead electrode andthe second lead electrode are set between the upper mold part and thelower mold part and that the exposed tip of the front surface protrusionabuts the upper mold part and the exposed tip of the back surfaceprotrusion abuts the lower mold part; pressing the upper mold partagainst the pair of lead electrodes; injecting a resin into the moldthat is in contact with the pair of lead electrodes; curing the injectedresin to harden the resin molded body; and removing the upper mold partfrom the lower mold part.

Still further, a method of manufacturing a light emitting deviceaccording to certain embodiments of the present disclosure includes,manufacturing a package according to the method of manufacturing apackage described in the embodiments of the present disclosure, andmounting a light emitting element on the recess formed in the package.

With the package and the light emitting device according to theembodiments of the present disclosure, production of burrs can besuppressed without reducing the output of an LED. Further, according tothe methods of manufacturing a package and a light emitting device ofthe present disclosure, a package and a light emitting device in whichproduction of burrs is suppressed without reducing the output of an LEDcan be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a cross section of a light emittingdevice according to one embodiment.

FIG. 2 is a schematic diagram of a cross section of the light emittingdevice according to one embodiment taken along line II-II in FIG. 1.

FIG. 3 is a partial schematic diagram of a cross-section of the lightemitting device according to one embodiment, showing a state of aplating layer.

FIG. 4 is a schematic diagram of a top view of the light emitting deviceaccording to one embodiment.

FIG. 5 is a schematic diagram of a bottom view of the light emittingdevice according to one embodiment.

FIG. 6 is a schematic diagram showing an arrangement of lead electrodesand the mold at the position corresponding to line II-II in FIG. 1 in astep of manufacturing the light emitting device according to oneembodiment.

FIG. 7 is a schematic diagram of a cross-section showing the leadelectrodes placed between and held by the upper mold part and the lowermold part, in a step of manufacturing a package for mounting a lightemitting element according to one embodiment.

FIG. 8 is a schematic diagram of a cross-section showing a state inwhich resin is injected and hardened, in a step of manufacturing apackage for mounting a light emitting element according to the secondembodiment.

FIG. 9 is a schematic diagram of a cross-section showing removing theupper mold part, in a step of manufacturing a package for mounting alight emitting element according to the second embodiment

FIG. 10 is a schematic diagram of a cross-section showing a state inwhich resin is injected and hardened at the position corresponding toline X-X in FIG. 1 in a step of manufacturing the light emitting deviceaccording to the second embodiment.

FIG. 11 is a schematic diagram of a cross-section showing a surfaceprotrusion formed by etching in the light emitting device according toone embodiment.

FIG. 12 is a schematic cross-sectional view showing the state of thesurface protrusion before and after placed between and pressed by themold, in a package according to one embodiment.

FIG. 13 is a schematic cross-sectional view showing a relationshipbetween the surface protrusion provided with a metal portion and asealing member in the light emitting device according to one embodiment.

FIG. 14 is a partial schematic diagram of a cross-section showing astate of a plating layer, in a step of manufacturing the light emittingdevice according to Variation 1.

FIG. 15 is a schematic diagram of a cross-section of lead electrodesprovided with lateral surface protrusion portions respectively accordingto Variation 2.

FIG. 16 is a schematic diagram of a top view of lead electrodes providedwith lateral surface protrusion portions respectively according toVariation 2.

FIG. 17 is a schematic cross-sectional view showing a positionalrelationship between a front surface protrusion and a resin molded bodyof a light emitting device according to Variation 3.

FIG. 18 is a schematic cross-sectional view showing a positionalrelationship between the front surface protrusion and the resin moldedbody and a mold of the light emitting device according to Variation 3.

FIG. 19 is a schematic cross-sectional view of a front protrusionprovided with a groove, showing a state before and after placed betweenand pressed by the mold according to Variation 4.

FIG. 20 is a schematic diagram of a cross-section of a light emittingdevice according to Variation 5 in which a die-bonding member is filledin a region for mounting a light emitting element.

DETAILED DESCRIPTION OF EMBODIMENTS Embodiments

In the following, embodiments will be described with reference to thedrawings. Each of the embodiments shown below exemplifies a lightemitting device embodying the technical idea of the present invention;the technical idea of the present invention is not limited to theembodiments shown below. Further, the size, material, shape, relativearrangement and the like of constituent components described in theembodiments are not intended to limit the scope of the present inventionthereto unless otherwise specified, and they are merely examples. Notethat, the size, positional relationship and the like in the drawings maybe exaggerated for the sake of clarity.

FIG. 1 is a schematic diagram of a cross section of a light emittingdevice according to one embodiment. FIG. 2 is a schematic diagram of across section of the light emitting device according to one embodimenttaken along line II-II in FIG. 1. FIG. 3 is a partial schematic diagramof a cross-section of the light emitting device according to oneembodiment, showing a state of a plating layer. FIG. 4 is a schematicdiagram of a top view of the light emitting device according to oneembodiment. FIG. 5 is a schematic diagram of a bottom view of the lightemitting device according to one embodiment.

A light emitting device 1 includes a package 90, a light emittingelement 2, wires W, and a sealing member 40.

The package 90 includes pair of lead electrodes 20 and 30 made of metalplates, a plating layer 60 covering the surface of the pair of leadelectrodes 20 and 30, and a resin molded body 10. The package 90 isprovided with a recess 10 a for storing the light emitting element 2.The pair of lead electrodes 20 and 30 are exposed at a bottom surface 10c of the recess 10 a.

The shape of the whole package 90 is approximately a rectangularparallelepiped. At the upper surface of the package 90, the cup-shapedrecess (a cavity) 10 a for storing the light emitting element 2 isformed. The package 90 is integrally retained by the resin molded body10 such that the pair of lead electrodes 20 and 30 made of metal platesare exposed outside the resin molded body 10 and at the bottom surface10 c of the recess 10 a.

The resin molded body 10 forms the area between the first lead electrode20 and the second lead electrode 30 at the bottom surface 10 c of therecess 10 a and a lateral surface 10 b of the recess 10 a, and retainsthe pair of lead electrodes 20 and 30. Thus, the resin molded body 10fixes the first lead electrode 20 and the second lead electrode 30.Further, the resin molded body 10 is formed such that one end of thefirst lead electrode 20 and the second lead electrode 30 protrude fromtwo opposing sides of the rectangle in a plan view. Further, the resinmolded body 10 is formed such that the first lead electrode 20 and thesecond lead electrode 30 are interposed between the other two sides ofthe rectangle in a plan view. Thus, the resin molded body 10 fixes thefirst lead electrode 20 and the second lead electrode 30, as beingspaced apart from each other, to the bottom surface 10 c of the recess10 a.

Further, at an outer surface 11 a of the resin molded body 10, a gatemark 50 is molded. The gate mark 50 is a protrusion resulting from acutting step being the secondary work, and is a remainder of a resinmolded body (gate) molded at an injection port portion when resin isinjected from the injection port of the mold. Herein, since thecross-sectional shape of an injection port 77, which will be describedbelow, is semicircular, the gate mark 50 is formed as a column having asemicircular cross section. That is, the shape of the gate mark 50 ismolded in accordance with the cross-sectional shape of the injectionport.

The height, length, and width of the resin molded body 10 are notparticularly limited, and can be selected as appropriate in accordancewith the purpose and the intended use. The material of the resin moldedbody 10 may be, for example, thermoplastic resin or thermosetting resin.The thermoplastic resin may be, for example, polyphthalamide resin,liquid crystal polymer, polybutylene terephthalate (PBT), unsaturatedpolyester or the like. The thermosetting resin may be, for example,epoxy resin, modified epoxy resin, silicone resin, modified siliconeresin or the like.

The recess 10 a has a lateral surface 10 b and a bottom surface 10 c,and has a shape of a frustum of a cone in which the width is narrowedtoward the bottom surface 10 c. The light emitted by the light emittingelement 2 is reflected by the lateral surface 10 b. The light can becondensed or diffused by changing the angle of the lateral surface 10 bas appropriate. The bottom surface 10 c is made up of the first leadelectrode 20, the second lead electrode 30, and a gap 10 e that is partof the resin molded body 10. The gap 10 e is provided between the firstlead electrode 20 and the second lead electrode 30 such that the firstlead electrode 20 and the second lead electrode 30 are notshort-circuited.

In order for the lateral surface 10 b of the recess 10 a to efficientlyreflect light, the resin molded body 10 may contain a light reflectivemember. The light reflective member is a material exhibiting high lightreflectivity, such as white filler of titanium oxide, glass filler,silica, alumina, zinc oxide or the like. A visible light reflectivity of70% or more, preferably 80% or more is preferable. In particular, areflectivity of 70% or more or 80% or more in the wavelength band oflight emitted by the light emitting element is preferable. Thecompounded amount of titanium oxide or the like may be in a range of 5weight % to 50 weight %, and preferably in a range of 10 weight % to 30weight %. However, the present invention is not limited thereto.

The first lead electrode 20 includes a first inner lead portion 20 a anda first outer lead portion 20 b.

The first inner lead portion 20 a refers to a lead portion positionedinside and under the resin molded body 10 in a plan view. The shape ofthe first inner lead portion 20 a is approximately a quadrangle in aplan view. However, the shape thereof is not limited thereto, and thefirst inner lead portion 20 a may be partially provided with a cutout, arecess, a projection or the like.

The first outer lead portion 20 b refers to a lead portion positionedoutside the resin molded body 10 in a plan view. The shape of the firstouter lead portion 20 b is a quadrangle in a plan view. However, theshape thereof is not limited thereto, and the first outer lead portion20 b may be partially provided with a cutout, a recess, a projection orthe like.

The second lead electrode 30 includes a second inner lead portion 30 aand a second outer lead portion 30 b.

The second inner lead portion 30 a refers to a lead portion positionedinside and under the resin molded body 10 in a plan view. The shape ofthe second inner lead portion 30 a is approximately a quadrangle in aplan view. However, the shape thereof is not limited thereto, and thesecond inner lead portion 30 a may be partially provided with a cutout,a recess, a projection or the like.

The second outer lead portion 30 b refers to a lead portion positionedoutside the resin molded body 10 in a plan view. The shape of the secondouter lead portion 30 b is a quadrangle in a plan view. However, theshape thereof is not limited thereto, and the second outer lead portion30 b may be partially provided with a cutout, a recess, a projection orthe like.

The first lead electrode 20 and the second lead electrode 30 are formedto be exposed outside the resin molded body 10 at the bottom surface ofthe package 90. The outer bottom surface of the package 90 is thesurface to be mounted on an external substrate. The first lead electrode20 and the second lead electrode 30 are arranged as being spaced apartfrom each other by the gap 10 e of the resin molded body 10, and used asthe anode electrode and the cathode electrode when the light emittingdevice is in use.

Note that, herein, though the second lead electrode 30 is formed to belonger than the first lead electrode 20, the length, width, andthickness of the first lead electrode 20 and the second lead electrode30 are not particularly limited, and can be selected as appropriate inaccordance with the purpose and the intended use. The first leadelectrode 20 and the second lead electrode 30 are formed usingelectrically conductive material such as iron, copper, phosphor bronze,copper alloy or the like. Further, in order to enhance reflectivity oflight from the light emitting element 2, the first lead electrode 20 andthe second lead electrode 30 are metal-plated with gold, silver, copper,aluminum or the like.

The first lead electrode 20 has a front surface protrusion 4, which is aprotrusion linearly formed along the resin molded body 10 at the bottomsurface 10 c of the recess 10 a, and along its periphery at the bottomsurface 10 c of the recess 10 a. That is, the first lead electrode 20 isprovided with the front surface protrusion 4 at the boundary between aportion subjected to wire bonding and the resin molded body 10.

Specifically, part of the front surface protrusion 4 is formed along thelateral surface of the resin molded body 10 structuring the lateralsurface 10 b of the recess 10 a, and another part thereof is formedalong the gap 10 e connecting the first lead electrode 20 and the secondlead electrode 30.

Further, the lateral surface 10 b of the recess 10 a is connectedcontinuously to an outer corner portion of the front surface protrusion4. That is, in a cross-sectional view, the lower portion of the lateralsurface 10 b of the recess 10 a is in contact with the position of theouter corner portion of the front surface protrusion 4, such that theupper surface of the front surface protrusion 4 and the lateral surface10 b of the recess 10 a are continuous to each other. Further, thelowermost surface connecting to the lateral surface 10 b of the recess10 a and the upper surface of the front surface protrusions 4 and 5 maybe on an identical plane. Even when an upper mold part 70 and the pairof lead electrodes 20 and 30 are misaligned, the bottom surface 10 c ofthe recess 10 a can be easily formed.

Further, the first lead electrode 20 has a back surface protrusion 6,which is a protrusion formed at the position on the back surfaceopposite to the position of the front surface protrusion 4. That is, theback surface protrusion 6 is formed on the back surface of the firstlead electrode 20 along the position where the front surface protrusion4 is formed.

The second lead electrode 30 has a front surface protrusion 5, which isa protrusion linearly formed along the resin molded body 10 at thebottom surface 10 c of the recess 10 a, and along its periphery at thebottom surface 10 c of the recess 10 a. That is, the second leadelectrode 30 is provided with the front surface protrusion 5 at theboundary between a portion where the light emitting element 2 is bondedby die bonding and the resin molded body 10.

Specifically, part of the front surface protrusion 5 is formed along thelateral surface of the resin molded body 10 structuring the lateralsurface 10 b of the recess 10 a, and another part thereof is formedalong the gap 10 e connecting the first lead electrode 20 and the secondlead electrode 30.

Further, the lateral surface 10 b of the recess 10 a is connectedcontinuously to an outer corner portion of the front surface protrusion5. That is, in a cross-sectional view, the lower portion of the lateralsurface 10 b of the recess 10 a is in contact with the position of theouter corner portion of the front surface protrusion 5, such that theupper surface of the front surface protrusion 5 and the lateral surface10 b of the recess 10 a are continuous to each other.

Further, the second lead electrode 30 has a back surface protrusion 7,which is a protrusion formed at the position on the back surfaceopposite to the position of the front surface protrusion 5. That is, theback surface protrusion 7 is formed on the back surface of the secondlead electrode 30 along the position where the front surface protrusion5 is formed.

Herein, the front surface protrusion 5 is annularly formed so as tosurround the region for mounting the light emitting element 2. Theregion for mounting the light emitting element 2 specifically refers tothe region in the second inner lead portion 30 a exposed at the bottomsurface 10 c of the recess 10 a (hereinafter referred to as the “lightemitting element mounting region”).

The front surface protrusions 4 and 5 and the back surface protrusions 6and 7 can be formed by subjecting the base material itself of the metalplates to work. In the present embodiment, the material of the pair oflead electrodes 20 and 30 and the material of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 areidentical, and the front surface protrusions 4 and 5 and the backsurface protrusions 6 and 7 are integrally formed with the pair of leadelectrodes 20 and 30.

The surface of the pair of lead electrodes 20 and 30 is covered by theplating layer 60. Note that, as used herein, the surface of the pair oflead electrodes 20 and 30 refers to the upper surface and the backsurface of each of the pair of lead electrodes 20 and 30. However, inthe present embodiment, the plating layer 60 is formed also at eachlateral surface of the first lead electrode 20 and the second leadelectrode 30 where the first lead electrode 20 and the second leadelectrode 30 are opposed to each other. Then, the respective tips of thefront surface protrusions 4 and 5 and the back surface protrusions 6 and7 are exposed outside the plating layer 60. That is, at the uppersurface of the front surface protrusions 4 and 5 and the lower surfaceof the back surface protrusions 6 and 7, the plating layer 60 is notprovided, and the metal plates are exposed. In this manner, in thepresent embodiment, the pair of lead electrodes 20 and 30 are providedwith the plating layer 60 except for at the outer lateral surface of thefirst lead electrode 20 and the outer lateral surface of the second leadelectrode 30, the upper surface of the front surface protrusions 4 and 5and the lower surface of the back surface protrusions 6 and 7.

A width A1 of each of the front surface protrusions 4 and 5 ispreferably 110 μm or more. By setting the width A1 of the front surfaceprotrusions 4 and 5 to 110 μm or more, the front surface protrusions 4and 5 can be easily formed. Further, in manufacturing the light emittingdevice 1, when the width A1 of the front surface protrusions 4 and 5 is110 μm or more, and resin is injected into the mold, provided that theresin flows onto the upper surface of the front surface protrusions 4and 5, the resin tends to stop midway on the upper surface of the frontsurface protrusions 4 and 5. Accordingly, the resin will not easily flowto reach the metal exposed portions on the first lead electrode 20 andthe second lead electrode 30, and the effect of suppressing a productionof resin burrs is enhanced. In order to more easily achieve theabove-described effects, the width A1 of the front surface protrusions 4and 5 is more preferably 130 μm or more and further preferably 150 μm ormore.

Note that, the metal exposed portion on the first lead electrode 20 isthe portion on the first lead electrode 20 at the bottom surface 10 c ofthe recess 10 a excluding the front surface protrusion 4, and the metalexposed portion on the second lead electrode 30 is the portion on thesecond lead electrode 30 at the bottom surface 10 c of the recess 10 aexcluding the front surface protrusion 5.

Further, the width A1 of the front surface protrusions 4 and 5 ispreferably 200 μm or less. In manufacturing the light emitting device 1,when the width A1 of the front surface protrusions 4 and 5 is 200 μm orless, the pressing force is more easily centered to the front surfaceprotrusions 4 and 5 when the pair of lead electrodes 20 and 30 arepressed by the mold. In order to more easily achieve the above-describedeffect, the width A1 of the front surface protrusions 4 and 5 is morepreferably 180 μm or less, and further preferably 150 μm or less.

Note that, the width A1 of the front surface protrusions 4 and 5 is thewidth excluding the thickness of the plating layer 60. Further, as willbe described below, the thickness of metal portions 14 formed by thefront surface protrusions 4 and 5 being crushed is not included. This isalso applicable to the width A2 of each of the back surface protrusions6 and 7.

A thickness B1 of each of the front surface protrusions 4 and 5 ispreferably from 5 μm to 50 μm inclusive. In manufacturing the lightemitting device 1, when the thickness B1 of the front surfaceprotrusions 4 and 5 is 5 μm or more, as will be described below, and thepair of lead electrodes 20 and 30 are pressed by the mold, thepossibility of the upper mold part being brought into contact with themetal exposed portions on the first lead electrode 20 and the secondlead electrode 30 becomes smaller. On the other hand, when the thicknessB1 of the front surface protrusions 4 and 5 is 50 μm or less, thethickness of the entire pair of lead electrodes 20 and 30 can bereduced. In order to more easily achieve the effect described above, thethickness B1 of the front surface protrusions 4 and 5 is more preferably10 μm or more, and further preferably 15 μm or more. Further, in orderto further easily achieve the above-described effect, the thickness B1of the front surface protrusions 4 and 5 is more preferably 45 μm orless, and further preferably 40 μm or less.

Note that, the thickness B1 of the front surface protrusions 4 and 5 inthe light emitting device 1 is the thickness of the front surfaceprotrusions 4 and 5 after the package 90 is manufactured, and thethickness from which the thickness of the plating layer 60 is removed.This is also applicable to the thickness B2 of each of the back surfaceprotrusions 6 and 7.

A width A2 of each of the back surface protrusions 6 and 7 is preferably110 μm or more. By setting the width A2 of the back surface protrusions6 and 7 to 110 μm or more, the back surface protrusions 6 and 7 can beeasily formed. Further, by setting the width A2 of the back surfaceprotrusions 6 and 7 to 110 μm or more, when the light emitting device 1is mounted on an external substrate, since the back surface protrusions6 and 7 are in contact with the mounting surface of the substrate over awide area, excellent heat dissipation can be realized. Furthermore, inmounting the light emitting device 1, the bonding member becomes lesslikely to enter between the first lead electrode 20 and the second leadelectrode 30. In order to more easily achieve the above-describedeffect, the width A2 of the back surface protrusions 6 and 7 is morepreferably 130 μm or more, and further preferably 150 μm or more.

Further, the width A2 of the back surface protrusions 6 and 7 ispreferably 200 μm or less. In manufacturing the light emitting device 1,when the width A2 of the back surface protrusions 6 and 7 is 200 μm orless, and the pair of lead electrodes 20 and 30 are pressed by the mold,the pressing force will be more easily centered to the back surfaceprotrusions 6 and 7. In order to more easily achieve the above-describedeffect, the width A2 of the back surface protrusions 6 and 7 is morepreferably 180 μm or less, and further preferably 150 μm or less.

A thickness B2 of each of the back surface protrusions 6 and 7 ispreferably from 5 μm to 50 μm inclusive. In manufacturing the lightemitting device 1, when the thickness B2 of the back surface protrusions6 and 7 is 5 μm or more, as will be described later, and the pair oflead electrodes 20 and 30 are pressed by the mold, the possibility ofthe lower mold part being brought into contact with the pair of leadelectrodes 20 and 30 becomes smaller. Further, in mounting the lightemitting device 1, the bonding member becomes less likely to enterbetween the first lead electrode 20 and the second lead electrode 30. Onthe other hand, when the thickness B2 of the back surface protrusions 6and 7 is 50 μm or less, the thickness of the entire pair of leadelectrodes 20 and 30 can be reduced. In order to more easily achieve theabove-described effect, the thickness B2 of the back surface protrusions6 and 7 is more preferably 10 μm or more, and further preferably 15 μmor more. Further, in order to more easily achieve the above-describedeffect, the thickness B2 of the back surface protrusions 6 and 7 ispreferably 45 μm or less, and further preferably 40 μm or less.

Note that, the width and thickness of the front surface protrusions 4and 5 and the back surface protrusions 6 and 7 are changed asappropriate depending on the material of the first lead electrode 20 andthe second lead electrode 30, the size of the resin molded body and thelike.

The light emitting element 2 is mounted on the second lead electrode 30of the package 90. The shape or size of the light emitting element 2used herein is not particularly limited. As to the color of lightemitted by the light emitting element 2, an arbitrary wavelength can beselected in accordance with the intended use. For example, as a lightemitting element of blue (wavelength 430 nm to 490 nm), GaN-base orInGaN-base may be employed. The InGaN-base may beIn_(X)Al_(Y)Ga_(1-X-Y)N (0≦X≦1, 0≦Y≦1, X+Y<1) or the like.

The wires W are electrically conductive wires for electricallyconnecting the light emitting element 2 and electrical components suchas a protective element to the first lead electrode 20 and the secondlead electrode 30. The material of the wires W may be metal such as Au(gold), Ag (silver), Cu (copper), Pt (platinum), Al (aluminum) or thelike, and alloy thereof. Particularly, Au being excellent in thermalconductivity and the like is preferable. Note that, the thickness of thewire W is not particularly limited, and can be selected as appropriatein accordance with the purpose and the intended use.

The sealing member 40 is provided in the recess 10 a of the package 90so as to cover the light emitting element 2 and the like. The sealingmember 40 is provided for protecting the light emitting element 2 andthe like from an external force, dust, moisture and the like, and toimprove the heat resistance, weather resistance, and lightfastness ofthe light emitting element 2 and the like. The material of the sealingmember 40 may be thermosetting resin, e.g., a transparent material suchas silicone resin, epoxy resin, urea resin or the like. In addition tosuch a material, for obtaining a prescribed function, a fluorescentmaterial or filler of a substance exhibiting high light reflectivity maybe added to the sealing member 40.

For example, by mixing the sealing member 40 and a fluorescent material,color-tone adjustment of the light emitting device 1 can be easilyachieved. Note that, such a fluorescent material may be the one greaterin specific gravity than the sealing member 40, and absorbing the lightfrom the light emitting element 2 to convert the wavelength. When thefluorescent material is greater in specific gravity than the sealingmember 40, it precipitates toward the first lead electrode 20 and thesecond lead electrode 30 and therefore it is preferable. Specifically,for example, a yellow fluorescent material such as YAG (Y₃Al₅O₁₂:Ce),silicate or the like, a red fluorescent material such as CASN(CaAlSiN₃:Eu) or KSF (K₂SiF₆:Mn) or the like, or a green fluorescentmaterial such as chlorosilicate, BaSiO₄:Eu²⁺ or the like may be used.

As the filler contained in the sealing member 40, for example asubstance exhibiting high light reflectivity such as SiO₂, TiO₂, Al₂O₃,ZrO₂, MgO or the like may be suitably used. Further, for the purpose ofcutting undesired wavelengths, for example, an inorganic or organiccoloring dye or coloring pigment may be used.

Method of Manufacturing a Light Emitting Device

Next, a description will be given of a method of manufacturing the lightemitting device according to the present embodiment. FIG. 6 is aschematic diagram showing an arrangement of lead electrodes and the moldat the position corresponding to line II-II in FIG. 1 in a step ofmanufacturing the light emitting device according to one embodiment.FIG. 7 is a schematic diagram of a cross-section showing the leadelectrodes placed between and held by the upper mold part and the lowermold part, in a step of manufacturing a package for mounting a lightemitting element according to one embodiment. FIG. 8 is a schematicdiagram of a cross-section showing a state in which resin is injectedand hardened, in a step of manufacturing a package for mounting a lightemitting element according to the second embodiment. FIG. 9 is aschematic diagram of a cross-section showing removing the upper moldpart, in a step of manufacturing a package for mounting a light emittingelement according to the second embodiment FIG. 10 is a schematicdiagram of a cross-section showing a state in which resin is injectedand hardened at the position corresponding to line X-X in FIG. 1 in astep of manufacturing the light emitting device according to the secondembodiment. FIG. 11 is a schematic diagram of a cross-section showing asurface protrusion formed by etching in the light emitting deviceaccording to one embodiment. FIG. 12 is a schematic cross-sectional viewshowing the state of the surface protrusion before and after placedbetween and pressed by the mold, in a package according to oneembodiment. FIG. 13 is a schematic cross-sectional view showing arelationship between the surface protrusion provided with a metalportion and a sealing member in the light emitting device according toone embodiment.

While not shown herein, a lead frame is used in which a plurality ofpairs of metal plates each being the pair of the first lead electrode 20and the second lead electrode 30 are connected by suspension leads.Further, the pair of metal plates on the lead frame are referred to asthe first lead electrode 20 and the second lead electrode 30.

The method of manufacturing the light emitting device 1 according to thepresent embodiment includes, as one example, the following first toeleventh steps.

The first step is a step of preparing the first lead electrode 20 andthe second lead electrode 30.

The structure of the first lead electrode 20 and the second leadelectrode 30 are as described above, and the front surface protrusions 4and 5 and the back surface protrusions 6 and 7 are previously formed.

The front surface protrusions 4 and 5 and the back surface protrusions 6and 7 can be formed by subjecting the base material itself of the metalplates to work such as, for example, etching or pressing.

When the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 are formed by etching, the pair of lead electrodes20 and 30 are covered by a mask of a prescribed shape, and immersed inetchant. Therefore, the lateral surface of the front surface protrusions4 and 5 and the back surface protrusions 6 and 7 becomes slightlyrounded (see FIG. 11). On the other hand, when the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 are formedby pressing, the lateral surface of the front surface protrusions 4 and5 and the back surface protrusions 6 and 7 become perpendicular andprovided with corners (see FIG. 3).

Further, the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 crush when pressed by the mold, depending on thepressing pressure. Therefore, the thickness of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 ispreferably designed such that thicknesses B1 and B2 of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 become 5 μmto 50 μm inclusive when pressed, taking into consideration the pressingpressure.

The second step is a step of forming the plating layer 60 on the surfaceof the pair of lead electrodes 20 and 30 such that at least the tips ofthe front surface protrusions 4 and 5 and the back surface protrusions 6and 7 are exposed. The place where the plating layer 60 is formed is asdescribed above.

The plating layer 60 can be formed by electroless plating orelectroplating. Further, in order to allow the tips of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 to beexposed outside the plating layer 60, for example, a mask may be used,or the plating layer 60 at the tips of the front surface protrusions 4and 5 and the back surface protrusions 6 and 7 may be removed by etchingafter formation of the plating layer 60. The method of electrolessplating or electroplating is not particularly limited, and should beperformed according to any conventional method.

Then, before performing the third step, as shown in FIG. 6, the firstlead electrode 20 and the second lead electrode 30 are arranged betweenthe upper mold part 70 and the lower mold part 71. The first leadelectrode 20 and the second lead electrode 30 are arranged as spacedapart by the gap 10 e (see FIG. 2) for preventing short-circuiting. Atthis time, the lower mold part 71 abuts the tip of the back surfaceprotrusion 7 of the second lead electrode 30, and the lower mold part 71abuts the tip of the back surface protrusion 6 of the first leadelectrode 20. Note that, the upper mold part 70 has a projection 75corresponding to the shape of the recess 10 a, in order to form therecess 10 a for storing the light emitting element 2 by the pair of leadelectrodes 20 and 30 and the resin molded body 10.

The third step is a step of, for example, using a package-manufacturingpurpose mold K, pressing the pair of lead electrodes 20 and 30 so as toallow the exposed tips of the front surface protrusions 4 and 5 to abutthe upper mold part 70, and allow the exposed tips of the back surfaceprotrusions 6 and 7 to abut the lower mold part 71. Here, as shown inFIG. 7, the first lead electrode 20 and the second lead electrode 30 arepressed between the upper mold part 70 and the lower mold part 71.

Specifically, a second outer portion 74 b of the upper mold part 70abuts the portion corresponding to the second outer lead portion 30 b ofthe second lead electrode 30, and a second bottom surface 75 b formed atthe projection 75 of the upper mold part 70 abuts the front surfaceprotrusion 5 of the second lead electrode 30. Further, a first outerportion 74 a of the upper mold part 70 abuts the portion correspondingto the first outer lead portion 20 b of the first lead electrode 20, anda first bottom surface 75 a formed at the projection 75 of the uppermold part 70 abuts the front surface protrusion 4 of the first leadelectrode 20. Thus, by the upper mold part 70 and the lower mold part71, space portions 80 and 81 are formed.

A third bottom surface 75 c formed at the projection 75 of the uppermold part is formed in a projecting manner between the first bottomsurface 75 a and the second bottom surface 75 b. This is to avoidformation of a clearance between the first lead electrode 20 and thesecond lead electrode 30.

However, it is also possible that the projection 75 of the upper moldpart 70 is formed flat, and the first bottom surface 75 a, the secondbottom surface 75 b, and the third bottom surface 75 c are flush withone another. In this case, the front surface protrusion 4 of the firstlead electrode 20, the front surface protrusion 5 of the second leadelectrode 30, and the gap 10 e are on an identical plane and flush withone another. Further, in addition to the lower mold part 71, the gap 10e corresponding to the area between the back surface protrusion 6 of thefirst lead electrode 20 and the back surface protrusion 7 of the secondlead electrode 30 may be flat, and the upper surface of the lower moldpart 71 may be flush. In this case, the back surface protrusion 6 of thefirst lead electrode 20, the back surface protrusion 7 of the secondlead electrode 30, and the gap 10 e are on an identical plane and flushwith one another.

In the third step, the first lead electrode 20 and the second leadelectrode 30 are pressed by the mold by a pressing force with whichcontact between the second bottom surface 75 b formed at the projection75 of the upper mold part 70 and the metal exposed portion of the secondlead electrode 30 is avoided, and contact between the first bottomsurface 75 a and the metal exposed portion of the first lead electrode20 is avoided. At this time, though the front surface protrusions 4 and5 crush when being pressed depending on the pressing pressure, thesecond bottom surface 75 b does not abut the metal exposed portion ofthe second lead electrode 30, and hence, a space portion 82 is formed.Similarly, since the first bottom surface 75 a does not abut the metalexposed portion of the first lead electrode 20, a space portion 83 isformed.

Further, though the back surface protrusions 6 and 7 crush when beingpressed depending on the pressing pressure, the lower mold part 71 doesnot abut the metal exposed portion of the second lead electrode 30, andhence, a space portion 85 is formed. Similarly, with the lower mold part71, since the first bottom surface 75 a does not abut the metal exposedportion of the first lead electrode 20, a space portion 84 is formed.Note that, the metal exposed portions at the back surface of the pair oflead electrodes 20 and 30 are the portions at the back surface of thepair of lead electrodes 20 and 30 excluding the back surface protrusions6 and 7.

In the third step, preferably, pressing is performed such that thethicknesses B1 and B2 of the front surface protrusions 4 and 5 and theback surface protrusions 6 and 7 in the manufactured light emittingdevice 1 becomes 5 μm to 50 μm inclusive.

The fourth step is a step of injecting a resin J into thepackage-manufacturing purpose mold K pressing the pair of leadelectrodes 20 and 30. Herein, as shown in FIGS. 7 and 8, the resin J isinjected into the space portions 80 and 81 formed by the upper mold part70 and the lower mold part 71 from the injection port 77 by transfermolding. In the fourth step, since the first lead electrode 20 and thesecond lead electrode 30 are pressed by the upper mold part 70 and thelower mold part 71, the first lead electrode 20 and the second leadelectrode 30 do not flap when the resin J is injected. Thus, productionof burrs can be suppressed. Note that, since the pair of lead electrodes20 and 30 are provided with the front surface protrusions 4 and 5 andthe back surface protrusions 6 and 7, the resin J is less prone to enterthe space portions 82, 83, 84, and 85.

The fifth step is a step of forming the resin molded body 10 by curingthe resin J injected into the package-manufacturing purpose mold K.Herein, when thermosetting resin such as epoxy resin is injected as theresin J, for example, the upper mold part 70 and the lower mold part 71are heated to thereby heat the resin J for a prescribed period, to allowthe resin J to cure. Note that, when thermoplastic resin such aspolyphthalamide resin, for example, is injected, molding can be achievedthrough injection molding. In this case, the thermoplastic resin may bemelted under high temperatures, put into a low-temperature mold andallowed to cure by being cooled.

The sixth step is a step of removing the upper mold part 70 and thelower mold part 71. Herein, for example, as shown in FIG. 9, the uppermold part 70 is removed. Thus, the package in which the first leadelectrode 20 and the second lead electrode 30 are integrally retained bythe resin molded body 10 is completed.

Note that, when the resin J is cured in the fifth step, in a crosssection including the injection port 77 of the upper mold part 70, i.e.,in a cross section taken along line X-X in FIG. 1, as shown in FIG. 10,a gate 86 is molded at the injection port 77 portion. The gate 86 is cutby a known cutting machine along the outer surface 11 a of the resinmolded body 10 after the upper mold part 70 is removed (the seventhstep). Thus, the gate mark 50 is formed as the mark remaining when thegate 86 is cut off.

The eighth step is a step of mounting the light emitting element 2 inthe recess 10 a formed at the package 90. In the present embodiment, thelight emitting element 2 is an element having the one-surface electrodestructure in which a pair of n-electrode and p-electrode are formed onthe upper surface. In this case, the back surface of the light emittingelement 2 is bonded to the second lead electrode 30 by an insulatingdie-bonding member. One electrode on the upper surface of the lightemitting element 2 is connected to the first lead electrode 20 by thewire W, and the other electrode on the upper surface of the lightemitting element 2 is connected to the second lead electrode 30 by thewire W.

The ninth step is a step of packing the sealing member 40 into therecess 10 a of the package 90 so as to cover the light emitting element2. Here, as shown in FIG. 2, the sealing member 40 is applied inside therecess 10 a surrounded by the resin molded body 10 of the package 90, tothereby seal the light emitting element 2. At this time, the sealingmember 40 is dripped to reach the upper surface of the recess 10 a ofthe resin molded body 10. The sealing member 40 may be packed into therecess 10 a of the resin molded body 10 by, for example, injection,compression, or extrusion. It is preferable that a fluorescent materialis previously mixed with the sealing member 40. Thus, the color of thelight emitting device can be adjusted easily.

The tenth step is a step of curing the sealing member 40 packed into therecess 10 a. Here, when thermosetting resin such as silicone resin, forexample, is injected as the sealing member 40, the resin is heated for aprescribed period and cured.

The eleventh step is a step of cutting off the package 90 from the leadframe. Herein, the resin molded body 10 and the pair of lead electrodes20 and 30 are cut off from the lead frame, whereby the package 90 issingulated. Here, as a jig for cutting the suspension leads of the leadframe, for example, a lead cutter may be used.

Through the foregoing steps, the light emitting device 1 can be formed.

As has been described in the foregoing, with the method of manufacturingthe package according to the present embodiment, as shown in FIGS. 7 and8, the first lead electrode 20 and the second lead electrode 30 arepressed by the upper mold part 70 and the lower mold part 71. When theresin J is injected, the pressed area is smaller than that in the casewhere the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 do not exist at the lead electrodes. Accordingly,the pressing force is centered at the front surface protrusions 4 and 5and the back surface protrusions 6 and 7, and the upper mold part 70 andthe lower mold part 71 are brought into intimate contact with the firstlead electrode 20 and the second lead electrode 30. Further, since thefront surface protrusions 4 and 5 and the back surface protrusions 6 and7 are provided at the same position on the front and back surfaces ofthe first lead electrode 20 and the second lead electrode 30, thepressing force becomes more prone to be centered at the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7. Further,since the plating layer 60 is not formed at the tips of the frontsurface protrusions 4 and 5 and the back surface protrusions 6 and 7,the pressing force becomes more prone to be centered at the frontsurface protrusions 4 and 5 and the back surface protrusions 6 and 7.

Accordingly, the resin J will not easily flow into the space portions 82and 83, that is, onto the metal exposed portions on the first leadelectrode 20 and the second lead electrode 30. Thus, with the packageand the light emitting device according to the embodiment, production ofburrs can be suppressed.

Accordingly, a step of removing burrs of the bottom surface 10 c of therecess 10 a, which is otherwise conventionally required after the stepof molding the package, can be eliminated. Therefore, according to themethods of manufacturing the package and the light emitting deviceaccording to the embodiment, the package and the light emitting devicewith which production of burrs can be suppressed can be manufacturedeasily. As a result, a reduction in costs and lead time can be achieved.

Furthermore, the resin J will not easily flow into the space portions 84and 85. Thus, with the package and the light emitting device accordingto the embodiment, a step of removing burrs at the back surface of thepackage can be eliminated.

In addition, as in the conventional case where the front surfaceprotrusions 4 and 5 do not exist at the lead electrodes, when the leadframe is pressed by the mold, marks resulting from the work using themold remain, and the degree of a shine of the surface of the platinglayer 60 on the first lead electrode 20 and the second lead electrode 30is changed by the pressing pressure and heat of the mold. Accordingly,even when the degree of a shine of the surface of the plating layer 60on the first lead electrode 20 and the second lead electrode 30 isincreased before molding, the degree of a shine is reduced aftermolding. Then, the luminous flux of the LED is reduced, and the outputis also reduced.

However, since the front surface protrusions 4 and 5 exist at the firstlead electrode 20 and the second lead electrode 30 according to theembodiment of the invention, the first bottom surface 75 a and thesecond bottom surface 75 b formed at the projection 75 of the upper moldpart 70 will not be brought into contact with the metal exposed portionsof the first lead electrode 20 and the second lead electrode 30.Therefore, molding can be achieved without reducing the degree of ashine of the plating of the first lead electrode 20 and the second leadelectrode 30. Thus, the conventional problem of a reduction in theoutput of the LED can be solved.

Further, since the front surface protrusions 4 and 5 and the backsurface protrusions 6 and 7 exist at the first lead electrode 20 and thesecond lead electrode 30, the area pressed by the mold is smaller thanthat in the conventional case. Since the pressing pressure is centeredat the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7, the number of LEDs that can be manufactured fromone lead frame can be increased.

Still further, since the pressing pressure is centered only at the frontsurface protrusions 4 and 5 and the back surface protrusions 6 and 7,the pressing pressure of the package-manufacturing purpose mold K itselfcan be reduced, for example, to about half as great as that of theconventional mold. As a result, the effect of an increase in the life ofthe mold apparatus can also be attained.

Still further, since the front surface protrusions 4 and 5 are formed atthe first lead electrode 20 and the second lead electrode 30, thecontact area relative to the sealing member 40 increases, wherebyadhesion to the sealing member 40 improves. Still further, as shown inFIG. 12, since the front surface protrusions 4 and 5 and the backsurface protrusions 6 and 7 crush when being pressed, part of the metalof the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 squeezes out in the lateral direction, to form ametal portion 14. As shown in FIG. 13, by the sealing member 40 enteringbelow the metal portion 14, the sealing member 40 is prevented fromcoming off upward. Note that, the annular shape of the front surfaceprotrusions 4 and 5 also contributes to preventing the sealing member 40from coming off.

Still further, since the package 90 is molded without reducing thedegree of a shine of the surface of the plating layer 60 on the firstlead electrode 20 and the second lead electrode 30 exposed at the recess10 a, a reduction in the luminous flux of the light emitting device 1can be suppressed, and a reduction in the output can be prevented.

Still further, since the front surface protrusions 4 and 5 exist at thefirst lead electrode 20 and the second lead electrode 30, flow-out(bleeding) of the die-bonding member in mounting the light emittingelement 2 can be suppressed. In particular, when a plurality of lightemitting elements 2 are mounted, flow-out of the die-bonding member inthe lateral direction becomes a concern. However, when the width A1 ofthe front surface protrusions 4 and 5 is 110 μm or more, the die-bondingmember will not easily flow over the front surface protrusions 4 and 5.

Still further, since the back surface protrusions 6 and 7 exist at thefirst lead electrode 20 and the second lead electrode 30, in mountingthe light emitting device 1, a bonding member such as solder paste orthe like can be injected into the regions surrounded by the back surfaceprotrusions 6 and 7. Thus, bonding strength can be improved. Further,leakage of the bonding member in the lateral direction is prevented,whereby short-circuiting caused by the bonding member entering betweenthe first lead electrode 20 and the second lead electrode 30 isprevented. When the width A2 of the back surface protrusions 6 and 7 is110 μm or more, the bonding member will not easily flow over the backsurface protrusions 6 and 7. Further, by setting the thickness of theback surface protrusions 6 and 7 to an identical value, stability inmounting the light emitting device 1 improves.

EXAMPLE Example 1

In the following, Example 1 of the present invention will be described.Molding was performed using, as shown in FIGS. 2 and 3, the first leadelectrode 20 and the second lead electrode 30 provided with the frontsurface protrusions 4 and 5 at the boundary between the metal exposedportions of the first lead electrode 20 and the second lead electrode 30and the resin molded body 10, and with the back surface protrusions 6and 7 at the position on the back surface opposite to the position ofthe front surface protrusions 4 and 5, using a transfer molding machine.

The molding was performed under the conventional pressing pressure andinjection pressure conditions with which resin burrs were produced whenmolding was performed using conventional lead electrodes without thefront surface protrusions 4 and 5 and the back surface protrusions 6 and7. Then, whether or not burrs were produced was checked.

As a result, it was found that burrs were not produced at the metalexposed portions of the first lead electrode 20 and the second leadelectrode 30, with the first lead electrode 20 and the second leadelectrode 30 provided with the front surface protrusions 4 and 5 and theback surface protrusions 6 and 7. Further, it was found that burrs werenot produced at the back surface of the first lead electrode 20 and thesecond lead electrode 30.

Still further, it was found that the second bottom surface 75 b formedat the projection 75 of the upper mold part 70 was not brought intocontact with the metal exposed portion of the second lead electrode 30exposed at the recess 10 a of the package 90. This metal exposed portionis the central portion of the second inner lead portion 30 a excludingthe front surface protrusion 5.

Still further, it was found that the first bottom surface 75 a formed atthe projection 75 of the upper mold part 70 was not brought into contactwith the metal exposed portion of the first lead electrode 20 exposed atthe recess 10 a of the package 90. This metal exposed portion is thecentral portion of the first inner lead portion 20 a excluding the frontsurface protrusion 4.

VARIATIONS

Next, a description will be given of Variations of the light emittingdevice according to the present embodiment.

Variation 1

FIG. 14 is a partial schematic diagram of a cross-section showing astate of a plating layer, in a step of manufacturing the light emittingdevice according to Variation 1.

In the embodiment described above, the tips of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 are exposedoutside the plating layer 60. On the other hand, in Variation 1, thetips of the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 are covered by the plating layer 60. Furthermore, inthe embodiment described above, the widths A1 and A2 of the frontsurface protrusions 4 and 5 and the back surface protrusions 6 and 7 arepreferably 110 μm or more. On the other hand, in Variation 1, the widthA1 and A2 of the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 must be 110 μm or more. Other configurations aresimilar to that in the embodiment described above.

With such a structure, except that the tips of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 are exposedoutside the plating layer 60, the effect achieved by provision of thefront surface protrusions 4 and 5 and the back surface protrusions 6 and7, and the effect achieved by the widths A1 and A2 of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 being 110μm or more can be obtained.

Further, in a method of manufacturing the package according to Variation1, in the second step, the tips of the front surface protrusions 4 and 5and the back surface protrusions 6 and 7 are covered by the platinglayer 60.

Variation 2

FIG. 15 is a schematic diagram of a cross-section of lead electrodesprovided with lateral surface protrusion portions respectively accordingto Variation 2. FIG. 16 is a schematic diagram of a top view of leadelectrodes provided with lateral surface protrusion portionsrespectively according to Variation 2.

The first lead electrode 20 and the second lead electrode 30 may berespectively provided with lateral surface protrusions 8 and 9 beingprotrusions formed in the width direction of respective lateral surfacesopposing each other, at the center in the height direction of thelateral surfaces. That is, the first lead electrode 20 and the secondlead electrode 30 respectively have the lateral surface protrusions 8and 9 protruding in the horizontal direction at the sites where the pairof lead electrodes 20 and 30 are connected by the resin molded body 10.

The lateral surface protrusion 8 of the first lead electrode 20 isformed by a prescribed thickness at the center in the height directionin a cross-sectional view. Further, in a top view, the lateral surfaceprotrusion 8 of the first lead electrode 20 is formed in the widthdirection of the first lead electrode 20, that is, in parallel with thelongitudinal direction of the gap 10 e connecting the first leadelectrode 20 and the second lead electrode 30, in the entire widthdirection of the first lead electrode 20.

The lateral surface protrusion 9 of the second lead electrode is formedby a prescribed thickness at the center in the height direction in across-sectional view. Further, in a top view, the lateral surfaceprotrusion 9 of the second lead electrode 30 is formed in the widthdirection of the second lead electrode 30, that is, in parallel with thelongitudinal direction of the gap 10 e connecting the first leadelectrode 20 and the second lead electrode 30, in the entire widthdirection of the second lead electrode 30.

The lateral surface protrusions 8 and 9 can be formed in the first leadelectrode 20 and the second lead electrode 30, for example, bysubjecting the base material itself of the metal plates, for example, towork of etching or pressing.

By provision of the lateral surface protrusions 8 and 9, with thepackage 90, adhesion between the first lead electrode 20 and the secondlead electrode 30 and the resin molded body 10 improves, and the firstlead electrode 20 and the second lead electrode 30 are more firmly fixedto each other. Note that, the thicknesses and lengths of the lateralsurface protrusions 8 and 9 are not particularly limited, and should beadjusted as appropriate.

Variation 3

FIG. 17 is a schematic cross-sectional view showing a positionalrelationship between a front surface protrusion and a resin molded bodyof a light emitting device according to Variation 3. FIG. 18 is aschematic cross-sectional view showing a positional relationship betweenthe front surface protrusion and the resin molded body and a mold of thelight emitting device according to Variation 3.

The lateral surface 10 b of the recess 10 a is on the front surfaceprotrusions 4 and 5, and may be connected continuously to the uppersurface of the front surface protrusions 4 and 5. That is, in thepackage 90, part of the front surface protrusions 4 and 5 is covered bythe resin molded body 10. In a cross-sectional view, the lower part ofthe lateral surface 10 b of the recess 10 a is in contact with theposition of the upper surface front surface protrusions 4 and 5, and theupper surface of the front surface protrusions 4 and 5 and the lateralsurface 10 b of the recess 10 a are continuously connected.

With such a structure, adhesion of the resin molded body 10 to the pairof lead electrodes 20 and 30 can be more improved.

In the method of manufacturing the package, in a step of pressing thefirst lead electrode 20 and the second lead electrode 30 by the mold,the first lead electrode 20 and the second lead electrode 30 are pressedsuch that the outer circumferential end of the projection 75 of theupper mold part 70 is arranged at a prescribed position at the uppersurface of the front surface protrusions 4 and 5.

When the first lead electrode 20 and the second lead electrode 30 arepressed by the mold, at the upper surface of the front surfaceprotrusions 4 and 5, the upper mold part 70 and the pair of leadelectrodes 20 and 30 may fail to be precisely set because of thermalexpansion of the lead electrodes attributed to the heat of the mold,variations in the dimension of the lead electrodes and the like.Accordingly, when the width of the front surface protrusions 4 and 5 isnarrow, the outer circumferential end of the projection 75 of the uppermold part 70 may not be arranged at a prescribed position at the uppersurface of the front surface protrusions 4 and 5. However, by settingthe width of the front surface protrusions 4 and 5 to 110 μm or more,the outer circumferential end of the projection 75 of the upper moldpart 70 can be arranged at a prescribed position of the upper surface ofthe front surface protrusions 4 and 5, and the lateral surface 10 b ofthe recess 10 a can be arranged on the front surface protrusions 4 and5.

Note that, it is preferable that the width of the front surfaceprotrusions 4 and 5 exposed outside the resin molded body 10 becomes 110μm or more.

Variation 4

FIG. 19 is a schematic cross-sectional view of a front protrusionprovided with a groove, showing a state before and after placed betweenand pressed by the mold according to Variation 4.

The light emitting device may have a groove portion 15 formed along thelongitudinal direction of the front surface protrusions 4 and 5 (i.e.,the direction perpendicular to the surface of FIG. 19, and the directionextending along the periphery of the bottom surface 10 c of the recess10 a) at the tip of each of the front surface protrusions 4 and 5, and agroove portion 15 formed along the longitudinal direction of the backsurface protrusions 6 and 7 (i.e., the direction corresponding to thelongitudinal direction of the front surface protrusions 4 and 5) at thetip of each of the back surface protrusions 6 and 7.

The front surface protrusions 4 and 5 are each provided with the grooveportion 15 of prescribed depth and shape formed along the longitudinaldirection of the front surface protrusions 4 and 5 at the center in thewidth direction of the upper surface. Similarly, the back surfaceprotrusions 6 and 7 are each provided with the groove portion 15 of aprescribed depth and shape formed along the longitudinal direction ofthe back surface protrusions 6 and 7 at the center in the widthdirection of the lower surface. In each groove portion 15, metal isburied, which metal resulting from the front surface protrusions 4 and 5and the back surface protrusions 6 and 7 being crushed and squeezed outin the lateral direction when pressing is performed with a pressingforce of a magnitude with which the front surface protrusions 4 and 5and the back surface protrusions 6 and 7 crush.

In such a method of manufacturing the light emitting device, firstly, inthe step of preparing the pair of lead electrodes 20 and 30, the grooveportion 15 is formed at the tip of each of the front surface protrusions4 and 5 and the back surface protrusions 6 and 7. Then, when the pair oflead electrodes 20 and 30 are pressed, depending on the pressingpressure, the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 crush, and part of metal of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 squeezesout in the lateral direction. Thus, the squeezed out metal is buried inthe groove portion 15, whereby production of the metal portion 14outside the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7 is prevented. Accordingly, while the groove portion15 in which metal is buried remains at each of the front surfaceprotrusions 4 and 5 and the back surface protrusions 6 and 7 in themanufactured package, the front surface protrusions 4 and 5 and the backsurface protrusions 6 and 7 will not have the metal portion 14.

Accordingly, in the light emitting device, when it is desired to keepthe shape of the front surface protrusions 4 and 5 and the back surfaceprotrusions 6 and 7, the groove portion 15 is preferably formed at thetip of each of the front surface protrusions 4 and 5 and the backsurface protrusions 6 and 7.

The depth, shape, position to be formed and the like of the grooveportion 15 are not limited, and should be adjusted as appropriate.Further, the groove portion 15 may be formed at the front surfaceprotrusions 4 and 5, or the back surface protrusions 6 and 7.

Variation 5

FIG. 20 is a schematic diagram of a cross-section of a light emittingdevice according to Variation 5 in which a die-bonding member is filledin a region for mounting a light emitting element.

The light emitting device may be structured such that the sealing member40 contains a first fluorescent material, and resin containing a secondfluorescent material being different from the first fluorescent materialin the emission wavelength is packed in the region for mounting thelight emitting element 2.

For example, as the first fluorescent material, a fluorescent materialemitting green-color light is mixed with the sealing member 40. As thesecond fluorescent material, a fluorescent material emitting red-colorlight is mixed with a die-bonding member 45. Then, the die-bondingmember 45 containing the second fluorescent material is packed in theregion for mounting the light emitting element 2 (the metal exposedportion of the second lead electrode 30), and the light emitting element2 is mounted. Thereafter, the sealing member 40 containing the firstfluorescent material is packed in the recess 10 a of the package 90, toobtain the light emitting device. Thus, the light emitting device beinga bright white-color light source can be obtained. Note that, as shownin FIG. 20, the die-bonding member 45 containing the fluorescentmaterial can also be packed in the metal exposed portion of the firstlead electrode 20.

The type and combination of the first fluorescent material and thesecond fluorescent material should be selected as appropriate asdesired.

OTHER VARIATIONS

Though it has been described that the front surface protrusions 4 and 5and the back surface protrusions 6 and 7 are respectively formed at thefirst lead electrode 20 and the second lead electrode 30 of the package90, it is also possible that the front surface protrusion and the backsurface protrusion are provided to only one of the lead electrodes.

Further, the lateral surface of the front surface protrusions 4 and 5 onthe metal exposed surface side may be inclined outward from bottom totop in a cross section. Such a structure improves the light extractingefficiency.

The recess 10 a of the package 90 may be formed into a cylindrical shapewithout being tilted. Further, the lateral surface 10 b of the recess 10a may not necessarily be flat. It is also possible to mold the lateralsurface 10 b to have an uneven surface, such that the adhesion at theinterface between the resin molded body 10 and the sealing member 40improves. Further, though the recess 10 a is molded to be circular in aplan view in the present embodiment, the recess 10 a may be molded to beelliptical. Still further, though the resin molded body 10 is molded tobe rectangular in the present embodiment, the resin molded body 10 maybe molded to have a circular, elliptical, or other polygonal shape in aplan view.

The lead electrodes should be provided, as in the present embodiment, byat least a pair of positive and negative electrodes (the first leadelectrode 20 and the second lead electrode 30). However, it is alsopossible that three or more lead electrodes are provided.

The light emitting element 2 can be mounted on the first lead electrode20 in place of the second lead electrode 30. When the light emittingdevice 1 includes, for example two light emitting elements 2, the lightemitting elements 2 may be respectively mounted on the first leadelectrode 20 and the second lead electrode 30. A protective element maybe mounted on the inner lead portion where the light emitting element isnot mounted. For example, by setting the width of the front surfaceprotrusions 4 and 5 to 110 μm or more, a protective element can bemounted on the front surface protrusion 4 of the first lead electrode 20or on the front surface protrusion 5.

The light emitting element 2 may be an element having the oppositeelectrode structure (the double-surface electrode structure) in which,for example, the n-electrode (or the p-electrode) is formed on the backsurface of the element substrate. Further, the light emitting element 2is not limited to the face-up type, and may be the face-down type. Withthe light emitting element of the face-down type, the wires can bedispensed with.

In the method of manufacturing the light emitting device 1, the lightemitting element 2 is previously mounted on the package 90 andthereafter singulated. However, the light emitting element 2 may bemounted on the singulated package 90.

The position where the wire W is connected may be the upper surface ofeach of the front surface protrusions 4 and 5. In suspending the wire W,the wire W can be more easily suspended when the height differencebetween the upper surface of the light emitting element 2 and theposition where the wire W is suspended is smaller, that is, when theposition where the wire W is suspended is high. Note that, when thewidth of the front surface protrusions 4 and 5 is 110 μm or more, thewire W is easily connected when the wire W is connected to the uppersurface of the front surface protrusions 4 and 5.

When the tips of the front surface protrusions 4 and 5 and the backsurface protrusions 6 and 7 are exposed outside the plating layer 60,the plating layer 60 may be provided solely to the upper surface of thepair of lead electrodes 20 and 30.

The light emitting device of the present embodiment is applicable for abacklight light source of a liquid crystal display, various illuminationdevices, various display apparatuses such as a large-screen display, anadvertisement, a destination guide and the like, and furthermore, animage reading apparatus in a digital video camera, a facsimile, acopier, a scanner and the like, a projector apparatus and the like.

As shown in the above descriptions, a package, a light emitting device,and methods of manufacturing the package and the light emitting devicein accordance with the representative embodiments have been describedherein, but the scope of the invention is not limited to the abovedescription, and should be widely understood based on the scope of theclaims. Further, based on the above description, it will be obvious thatvarious changes and modifications can be made therein without departingfrom the scope of the embodiments of the invention.

What is claimed is:
 1. A method of manufacturing a package for mountinga light emitting element, the method comprising: providing a pair oflead electrodes, each made of a metal plate, the metal plate of at leastone of the lead electrodes having a front surface protrusion and a backsurface protrusion, the front surface protrusion being formed in a shapeof a circular segment to surround a region for mounting a light emittingelement, and the back surface protrusion being formed at a position at aback surface of the metal plate opposite to a position of the frontsurface protrusion; forming a plating layer on a surface of each of thelead electrodes such that at least a tip of each of the front surfaceprotrusion and the back surface protrusion is exposed from the platinglayer; forming a package comprising the pair of lead electrodes and aresin molded body, the package having a recess, and the step of formingthe package comprising: providing a mold having an upper mold part and alower mold part, the upper mold part having a projection with a shapecorresponding to the recess, placing the first lead electrode and thesecond lead electrode in predetermined positions on the lower mold partsuch that the first lead electrode and the second lead electrode are setbetween the upper mold part and the lower mold part, the exposed tip ofthe front surface protrusion abuts the upper mold part, and the exposedtip of the back surface protrusion abuts the lower mold part, pressingthe upper mold part against the pair of lead electrodes, injecting aresin into the mold, curing the injected resin to form the resin moldedbody, and separating the upper mold part from the lower mold part. 2.The method of manufacturing a package according to claim 1, wherein thepair of lead electrodes pressed by the upper mold part and the lowermold part are integrally provided in a lead frame in which a pluralityof pairs of lead electrodes are connected, and the method furthercomprises cutting off the package from the lead frame.
 3. The method ofmanufacturing a package according to claim 1, wherein the front surfaceprotrusion has a width of 110 μm or more.
 4. The method of manufacturinga package according to claim 1, wherein the front surface protrusion hasa width of 200 μm or less.
 5. The method of manufacturing a packageaccording to claim 1, wherein the front surface protrusion has athickness from 5 μm to 50 μm.
 6. The method of manufacturing a packageaccording to claim 1, the back surface protrusion has a width of 110 μmor more.
 7. The method of manufacturing a package according to claim 1,the back surface protrusion has a width of 200 μm or less.
 8. The methodof manufacturing a package according to claim 1, wherein the backsurface protrusion has a thickness in a range of 5 μm to 50 μm.
 9. Themethod of manufacturing a package according to claim 1, wherein thefront surface protrusion and/or the back surface protrusion are formingby etching or pressing.
 10. The method of manufacturing a packageaccording to claim 1, wherein the front surface protrusion and/or theback surface protrusion are crushed when pressed by the upper mold part.11. The method of manufacturing a package according to claim 1, whereina part of an upper surface of the front surface protrusion is pressed bythe upper mold part.
 12. The method of manufacturing a package accordingto claim 1, wherein an upper surface of the front surface protrusion hasa groove.
 13. A method of manufacturing a light emitting devicecomprising: manufacturing a package according to the method ofmanufacturing a package according to claim 1; and mounting a lightemitting element in the recess of the package.
 14. The method ofmanufacturing a light emitting device according to claim 13, furthercomprising packing a sealing member in the recess so as to cover thelight emitting element.
 15. A method of manufacturing a package formounting a light emitting element, the method comprising: providing apair of lead electrodes, each made of a metal plate, the metal plate ofat least one of the lead electrodes having a front surface protrusionand a back surface protrusion, the front surface protrusion being formedin a shape of a circular segment to surround a region for mounting alight emitting element, and the back surface protrusion being formed ata position at a back surface of the metal plate opposite to a positionof the front surface protrusion; forming a plating layer on a surface ofeach of the lead electrodes; forming a package comprising the pair oflead electrodes and a resin molded body, the package having a recess,and the step of forming the package comprising: providing a mold havingan upper mold part and a lower mold part, the upper mold part having aprojection with a shape corresponding to the recess, placing the firstlead electrode and the second lead electrode in predetermined positionson the lower mold part such that the first lead electrode and the secondlead electrode are set between the upper mold part and the lower moldpart, the exposed tip of the front surface protrusion abuts the uppermold part, and the exposed tip of the back surface protrusion abuts thelower mold part, pressing the upper mold part against the pair of leadelectrodes, injecting a resin into the mold, curing the injected resinto form the resin molded body, and separating the upper mold part fromthe lower mold part.
 16. The method of manufacturing a package accordingto claim 15, wherein the pair of lead electrodes pressed by the uppermold part and the lower mold part are integrally provided in a leadframe in which a plurality of pairs of lead electrodes are connected,and the method further comprises cutting off the package from the leadframe.
 17. A method of manufacturing a light emitting device comprising:manufacturing a package according to the method of manufacturing apackage according to claim 15; and mounting a light emitting element inthe recess of the package.
 18. The method of manufacturing a lightemitting device according to claim 17, further comprising packing asealing member in the recess so as to cover the light emitting element.